Screw-propeller.



J. HOWDEN. SCREW PROPELLER. APPLICATION FILED MAR. so, 1908.

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SCREW PROPBLLER. APPLICATION FILED MAR. so, 1908.

Patented Jan. 4, 1910.

2 SHEETS-SHEET 2.

wrzacy JAMES HOWDEN, OF GLASGOW, SCOTLAND.

SCREW-PROPELLER.

Specification of Letters Patent.

Patented Jan. 4, 1910.

Application filed March 30, 1908. Serial No. 424,197.

in one piece; the spaces between the blades and the other parts beingwithout projections so that a free passage is given to the water and theaction of the propeller is made more effective; the diameter of the bossbeing made less than that of a spherical boss, and the blades being moresecurely fixed.

The invention is applicable to propellers in which the blades are placedon the boss so as to revolve in the same plane when the shaft is turnedwithout forward and aft movement, and also to propellers in which theblades are placed on the boss in different positions fore and aft ofeach other.

The invention consists broadly in forming the boss with a recessencircling the same into which recess the blades are fitted; said recessbeing formed either as a complete circle or as an interrupted circle oras a spiral, so that in entering into position the blades are movedcircumferentially and not longitudinally.

The invention is illustrated in the accompanying drawings in whichFigures 1 and 2 are, respectively, a longitudinal section and crosssection of a cylindrical propeller boss showing one form of propellerwith the blades entering a circular recess in the boss. Fig. 3 is a plancorresponding to Fig. 2 showing one blade in cross section. Figs. 4 and5 are each longitudinal sections showing modifications. Figs. 6 and 7are respectively a cross section and a side elevation showing analternative form in which the recess is formed as an interrupted circle.Figs. 8, 9 and 10 are respectively a cross section, elevation anddeveloped plan showing a further alternative form in which the recess isformed as a helix encircling the boss. Figs. 11., 12 and 13 are viewscorres onding to Figs. 8, 9 and 10 showing a modi cation.

As shown in Figs. 1, 2 and 3, A is a cylindrieal propeller boss, formedwith an annular groove B for receiving the bases or flanges of theblades G and formed with shoulders I) at intervals, the flanges havingprojections D on each side adapted to engage with the under sides ofsaid shoulders. One shell filling piece E between the bases of theblades is shown in Fig. 1, and two are shown in Fig. 2 which also showsone widened space F without the filling piece. In Fig. 3 one fillingpiece is shown on one side of the fixed blade and one widened space F onthe other side. The filling pieces are held in place by pins or thelike. In this construction the blades are put first into the widened oropen parts of the groove, then pushed along into exact. position in thepart of the groove where the projections D engage below the shoulders.In Fig. 3 two screw pins with heads sunk into recesses in the flange areshown; these pins assist in re sisting the strains on the blades inpropelling, but they are used chiefly to insure that the blades will bealways brought into exact position on the boss; said pins may however bedispensed with.

111 the modification shown in Fig. 4:, shoulders I) are formed on oneside only of the annular groove B, the base of each blade having aprojection D on one side only; the other side being held by screw pins,thin side filling or distance piece E being interposed.

In the modification shown in Fig. 5 the annular groove B is formedwithout shoulders, the blades being held on each side by screw pins.

In the alternative form shown in Figs. 6 and 7 the recess is formed asan interrupted circle, the fiat seats of the blades lying in a circularline and the bases or flanges of the blades C being segments of acylinder which when fixed in place complete the cylindrical boss, nofilling pieces being required. The blades C are shown as held in theboss by projections on each side of the flange fitting 1ntocorresponding recesses in the boss.

In the alternative form shown in Figs. 8,

9 and 10, the recess in the boss is formed as ahelix encircling theboss. Fig. 8, shows the groove or recess continued around the greaterpart of the circumference in dotted lines, and the circumferentialpositions of the blades C. Fig. 9 shows the blades C placed in differentpositions fore and aft on the boss A, the blades being sectionedcircumferentially close to the periphery of the boss and without theusual filletings. In the development of the circumference of the bossshown in Fig. 10 the helical groove or recess is shown as being of alength suificient to receive the three blades C. At each end of therecess short filling pieces E are shown; filling pieces E are interposedbetween the bases of the blades.

In Figs. 11, 12, and 13, three blades are shown with their flat basesplaced fore and aft on a cylindrical boss, three arrangements forsecuring the blades in the position being indicated at K, L, and M.

Having now described my invention what I claim and desire to secure byLetters Patent of the United States is 1' 1. In a screw propeller thecombination with a cylindrical boss formed with a recess encircling saidboss, of blades formed with correspondingly shaped bases adapted to fitsaid recess, and means for securing said blades in position.

2. In a screw propeller, the combination with a cylindrical boss formedwith a recess encirclin said boss, of blades formed with bases adaptedto fit said recess, and filling pieces fitted in said recess andinterposed between the blades.

3. In a screw propeller, the combination with a cylindrical boss formedwith a helical recess encircling said boss, of blades formed with basesadapted to fit said recess, and means for securing said blades inposition.

4. In a screw propeller, the combination with a cylindrical boss formedwith a recess encircling the boss, said recess formed with shoulders, ofblades formed with corre.-..

spondingly shaped bases adapted to fit said recess, and means forsecuring said blades in position.

5. In a screw propeller, the combination with a cylindrical boss formedwith a recess encircling said boss, said recess formed with shoulders,of blades formed with bases adapted to fit said recess, and fillingpieces in said recess and interposed between the blades.

6. In a'screw propeller, the combination with a cylindrical boss formedwith a helical recess encircling said boss, said recess formed withshoulders, of blades formed with bases adapted to fit said recess, andmeans securing said blades in position.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

JAMES HOIVDEN.

Vitnesses WVALLAon FAnnvEA'rnEn, JOHN MOCLEARY, Jr.

